Cloud Peak Energy shares are falling in their first day of trading Friday after the U.S. coal producer's initial public offering priced below expectations.
Shares fell 51 cents, or 3.4 percent, to $14.49 in morning trading.
Cloud Peak Energy Inc. sold 30.6 million shares at $15 each. It expected to price the offering between $16 per share and $18 per share.
The offering generated gross proceeds of $459 million. Underwriters can purchase up to an additional 4.6 million shares.
Previously, Denver-based Cloud Peak was a Rio Tinto subsidiary overseeing mines in a coal-rich region of the western U.S. A little more than a year ago, London-based Rio Tinto began considering options to divest its U.S. coal mining assets forming holding company, Cloud Peak.